1. Field of the Invention
The present invention relates to an inkjet recording apparatus.
2. Description of the Related Art
In an inkjet recording apparatus, a recording head has a certain distance to a recording medium, and an image is recorded onto the recording medium as a result of an ink discharged from the recording head flying through a space between the recording head and the recording medium and reaching the recording medium. Accordingly, when there is variation in the ink flight time and/or discharge vector, the ink landing positions on the recording medium become different from one another, causing image deterioration. The recording head is mounted in a carriage, which reciprocates in a direction intersecting with a transport direction of the recording medium, and thus, in order to provide favorable image recording, it is important to maintain the parallelism of reciprocation of the carriage and the flatness of the recording medium itself.
In order to maintain the parallelism of reciprocation of the carriage, that is, for a guide member for making the carriage run in parallel to a recording surface of the recording medium, a carriage shaft and a guide shaft are used. A carriage shaft movably supporting the carriage is a linear member. Since opposite ends of the carriage shaft are secured to the chassis, the carriage shaft slightly elastically deforms owing to its own weight and the weight of the carriage when the carriage moves along the carriage shaft. Accordingly, the distance between the recording head and the recording surface of the recording medium varies according to the position of the carriage when the carriage moves. As a result, variation occurs in the ink flight time, causing image deterioration.
In order to deal with the image deterioration resulting from variation in ink flight time, Japanese Patent Application Laid-Open No. 2007-136728 discloses a method in which ink discharge timing is changed according to the elastic deformation of a carriage shaft, and the moving direction and position of a carriage, thereby making an ink land at a target position.
However, the aforementioned method of changing the ink discharge timing is a method used for correcting deviation of an ink landing position from a target position on a recording medium in the carriage movement direction. Accordingly, in the aforementioned method, no consideration is given for the case where deviation of an ink landing position from a target position occurs in the recording medium transport direction, which intersects with the carriage movement direction.